They could heavily retool Cutthroat ala Rook into Swindle. Additionally, retool Blast Off so the wings can be swapped for train wheels. That said, I think body-shape wise, a jet would work better for Blitzwing.
For astrotrain take the uw blast off mold, include some new guns, that when plugged into the underside of the folded up wings, resemble train wheels.
For blitzwing, take cw skydive, add a couple of tread looking bits that can be plugged into the slots on the sides of his arms, and design a new handfootgun that resembles his tank turret.